Study Of Thermostability On High Isotactic Poly(1-Butene)

High isotactic poly1-butene （iPB） is a semicrystalline, plastic polymer with highresistant to long-term creep, abrasion and stress cracking. It retains its physicalproperties at elevated temperatures and it is particularly suitable for making pipes. So,it is need good thermalstability when iPB was used. There are many factors influencethe thermalstability, ash is one of the most important factors. The higher ash contentand the worse thermalstability limit the application of iPB in pipes, for this question iniPB which was synthetized by our laboratory. In this paper, iPB was synthesized byTiCl4/MgCl2-AlEt3catalyst system, and the polymerization rules were studied. Wereduced the ash content by optimize the polymerization and further reduced the ash bypost-treatment processing. We analysed the difference of ageing resistanceperformance between iPB samples with different ash content and proved the more ashcontent the worse thermalstability it has, the mechanism of catalyst residues promoteageing was also primarily discussed in this article.Optimizing the polymerization. The influence of external electron donors, theratio of Al and Ti, H₂to iPB was studied. Experiments shows that use the CS-1catalyst and under the polymerizing condition of DDS/Ti=10; Al/Ti=100andH₂=0.01MPa, lower ash content iPB was synthesized with isotacticity higher than95%and Melt Index at around0.4g/10min. We studied the constitute of ash by theoreticalcomputation and Energy Spectrum Analysis. We synthesized iPB with ash content ataround1500ppm combine the ash and usability by optimize the polymerization.Post-treatment technology research. Borrowing from the early industrialproduction method of polypropylene post-treatment processing, we explored thesuitable post-treatment processing. It shows that use the reagent3with C method,immediately washing the iPB under the boiling condition when the reaction finished. By this way,50%～90%ash can be removed, thus made the ash content of iPB can belower at around200ppm.The thermalstability of iPB samples with different catalysis residues was alsocharacterized. It has been proved by the way of gel permeation chromatography（GPC）,mechanics performance testing, thermogravimetric analysis（TG） and infraredspectroscopic analysis（FT-IR） that the samples which contants the lower catalystresidues has the better thermalstability. The mechanism of catalyst residues promoteageing was also primarily discussed in this article.